1. Turn off the RGA filament and disconnect it.

2. Record the pressure and then close the angle valve and gate valve on the RGA line to isolate it from the system.

3. Turn off the backing and turbo pump and let the turbo pump spin to a stop by slowly leaking the chamber. The slower the safer.

4.Slowly open the vents on the chamber and the turbo pump. Making sure not to raise the pressure too fast.

5. Once done venting the chamber, open the lid by removing the bolts and prying the lid open with a long flat head screw driver.

6. Removed previous parts and placed them into clean bags. Place new parts inside of the chamber and group them together close to the center.

7. Place the lid back onto the chamber and tighten the bolts in a circular pattern until tightened all the way with the wrench.

8. Make sure all vents are closed and turn the backing pump back on.

9. The turbo pump can be turned back on when the pressure reaches e-1 torr.

10. Wait until the chamber reaches a pressure of e-6 torr before opening the angle and gate valve on the RGA line. After the RGA line is open and the pressure is still below e-6 torr, the RGA filament can be turned on and a leak test of the lid should be performed.

11. After the leak test shows no leaks, proceed with starting the low temp bake.

I measured the temperature of the flanges where some of the electronics will go and I found that the RGA flange was at 55C and the two full range gauges were at 65C. I also stopped bake 9 to cool down for measurement.

Installed the heater elements into their fixture and prepped the cables by twisting the wires into pairs. We also installed the pins onto the wires and placed them into the peek DB 25 connector. The installation tool we had did not fit the pin size we had so the pins needed to be installed by hand by opening the connector and holding them in place. In the future we will need to make sure we twist the wires together, group them, and then splice them all to the same size for easier installation. We then grouped all the twisted pairs into a bundle and zipped them together. On the left with two peek zip ties is the power and on the right is the RTD with one peek zip tie. This orientation remains true when looking at the feed through flange from the outside with the power port on closest to the wall.

We also installed the heater elements numbered 1-8 starting from the left in image 3. These elements have numbers as resistance data was taken before as to identify the heaters after they are in the chamber. After installing the DB 25 connectors we tested that the pins were in the right orientation by using a volt meter and testing the resistance where the cable runs into the the actual power supply. It seems that all the pins were properly installed and the resistance values all match with each one gaining about 2 Ohms from the cable itself.

Then the pump down was started. The pump was very slow and we suspected a leak but after changing the o-ring pump down was not any faster and we decided to leave it over break as it seemed to just be water outgassing from the aluminum. The chamber is now able to be RGA scanned and leak tested before the next bake as it is low enough pressure.

Leak tested each flange and weld and only found two flanges to have noticeable leaks with the electron multiplier on. These were the turbo pump flange and the RGA flange that connects to the cross. The RGA one is rather new as it has not had a measurable leak before and it was around 2 e-8. We then applied the new sealant to these two flanges as directed by the instructions on the packaging.

Then after waiting a few minutes for the sealant to dry we started the bake. We got the PID controllers set to 120 after many steps and we checked the temperature of the flanges throughout this increase. The flanges never reached 70C with the electronics still left on it. The RGA was left on as well.

Below is the data for the most recent bake. I believe the chamber is cleaner than it is actually showing as the RGA data was still getting lower while the data was being taken. I will take the data again tomorrow just in case. Still, the data shows that the chamber is basically as clean as it was before bake 10 and this means further power testing can proceed.

Helium leak tested the chamber again today to check if the sealant changed anything. The two primary target flanges from last time have improved significantly with the flange from the RGA on the cross now being below 2e-14. While the turbo pump flange was leaking at a rate of 4e-13. Much better than what it has been before.

Heater 1= 73.6; 81.8

Heater 2= 70.4; 82.1

Heater 3= 71; 84.5

Heater 4= 71.5; 80

Heater 5= 70.5; 81.7

Heater 6= 72; 79.4

Heater 7= 69.2; 78.2

Heater 8= 71.1; 84.2

Took more data today and the chamber and elements are showing an even lower HC level than we have gotten before. It is safe to say that the elements are not contaminated and out gassing HC into the chamber.

Cleaned and baked the Cal Tech FROSTI legs and showed Luke the procedure on how to clean parts.

It should be noted that we can not have the zero length reducer and the gate valve on the same arm as they both have blind tapped holes. We need to decide if we want the gate valve or not as if we do, we will need to use the 3 inch long reducer.

Important Measurements:

From the back of the flange to the back of the RGA: 25.25 in

Height from bottom of the blank to the bottom of the chamber: 2.75 in

[Julian, Cao]

• 03:00 pm: Particle count
  1. : Zone 3
     • 0.3 um: 498
     • 0.5 um: 124
     • 1 um: 124
  2. : Zone 4
     • 0.3 um: 748
     • 0.5 um: 457
     • 1 um: 374
• 03:32 pm: Installing Pirani gauge onto pump line
• 03:51 pm: Finish installing Pirani gauge, start installing RGA probe
• 04:03 pm: Finish installing PRGA probe, start routing cable from gauge controller to Pirani gauge
• 04:30 pm: All ethernet cables are routed and connected to gauge controllers
• 04:48 pm: Power gauge controller up, all gauges are recognised and readout shows atmospheric pressure as expected (1000 mbar)
• 04:51 pm: End-of-work particle count
  1. : Zone 3
     • 0.3 um: 1413
     • 0.5 um: 872
     • 1 um: 623
  2. : Zone 4
     • 0.3 um: 374
     • 0.5 um: 166
     • 1 um: 166